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| Titel |
Transpacific transport of benzo[a]pyrene emitted from Asia |
| VerfasserIn |
Y. Zhang, S. Tao, J. Ma, S. Simonich |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 23 ; Nr. 11, no. 23 (2011-12-02), S.11993-12006 |
| Datensatznummer |
250010233
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| Publikation (Nr.) |
 copernicus.org/acp-11-11993-2011.pdf |
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| Zusammenfassung |
| A global-scale three dimensional atmospheric transport and chemistry model
was applied to simulate transpacific transport of Benzo[a]pyrene (BaP)
emitted from Asia. The model results were compared with observations at six
monitoring sites. The annual mean and seasonal variation of transport
patterns and the contributions of different Asian source regions to
transpacific transport flux were investigated. The episodic nature of
transpacific transport was also systematically explored. Interannual
variability of transpacific transport of BaP was also assessed during the
period of 1948–2007. Results showed that strong enhancements of modeled BaP
occurred in an area bounded by 70–80° E and 100–120° E. Air
containing these elevated BaP concentrations was then delivered eastward by
westerly winds. When approaching the West Coast of North America, the
descending atmospheric motion carried BaP-laden air into the lower
atmosphere. The transpacific transport flux was 1.6 times higher in the
winter than in the summer. East Asian emission dominates the transpacific
transport flux with a contribution of about 97%. Near ground
concentration of BaP induced by Asian sources in North America varied
between 1–20 pg m−3. A case study for observation at Cheeka Peak
Observatory during March 2002–May 2002 reveals the importance of warm
conveyor belt for transpacific transport. The number of days with
transpacific transport flux with a factor of 0.5, 1.0, 1.5, and 2.0 larger
than the running mean were 9.4%, 0.72%, 0.06% and 0.01%,
respectively, implying a mild contribution of episodic transport to the
long-term mean transport flux. Significant interannual fluctuation of
transpacific transport of BaP was found, including a general decreasing
trend during 1948–2007, and especially after the 1970s. The transpacific
transport was found to be positively correlated with the Southern
Oscillation Index. |
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